KR20230170677A - Imide-amic acid copolymer and its production method, varnish, and polyimide film - Google Patents

Abstract

Imide-amic acid copolymer, a precursor of polyimide resin, which can obtain a film with a low linear expansion coefficient, excellent heat resistance, and little change in yellowness even when heat treated at 400°C or higher, its production method, varnish, A polyimide film is provided. It includes a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2), and the molar ratio of the repeating unit represented by the formula (1) and the repeating unit represented by the formula (2) is 5. /95~60/40, imide-amic acid copolymer.

(A ¹ is an aromatic group with 4 to 39 carbon atoms or an aliphatic group with a norbonan skeleton, B ¹ and B ² are groups represented by formula (3), ^{A 2} is an aromatic group with 4 to 39 carbon atoms, ² is a hydrogen atom, an alkyl group with 1 to 6 carbon atoms, an alkylsilyl group with 3 to 9 carbon atoms, Y ¹ , Y ² is -COO- or -OCO-, R ¹ , R ² , R ³ is a group with 1 to 20 carbon atoms Device, h, i, j, k are 0~4.)

Description

Imide-amic acid copolymer and its production method, varnish, and polyimide film

The present invention relates to an imide-amic acid copolymer, which is a precursor of polyimide resin, a method for producing the same, a varnish containing the copolymer, and a polyimide film.

Polyimide resin is being considered for various uses in fields such as electrical and electronic components. For example, it is desired to replace glass substrates used in image display devices such as liquid crystal displays and OLED displays with plastic substrates for the purpose of making devices lighter and more flexible, and polyimide films suitable as such plastic substrates are needed. Research is in progress. Transparency and low yellowness are required for polyimide films for these applications.

In this regard, for example, in Patent Document 1, for the purpose of obtaining a polyimide film with low residual stress, little warpage, low yellowness, and high elongation, two types of specific A polyimide precursor characterized by containing amic acid structural units in a specific ratio is disclosed.

International Publication No. 2017/051827

As described above, transparency and low yellowness are required for polyimide films for specific applications. However, the device type of TFT is LTPS (Low Temperature Polysilicon TFT), and the process temperature exceeds 400℃, and the polyimide used as the substrate is required to have heat resistance that can withstand processing at a high temperature of 400℃ or higher multiple times, and such heat history is required. Also, it is required to maintain transparency and low yellowness.

In addition, as described above, due to concerns about peeling at the joint surface or deformation of the product due to the warping of the support due to the difference in linear expansion coefficient between the support and the difference in linear thermal expansion coefficient with the inorganic layer constituting the device, the linear expansion coefficient Reduction is also needed.

Patent Document 1 discloses a technique for reducing residual stress and reducing yellowness, but it is still insufficient, and in particular, it has not been possible to obtain a polyimide film with excellent heat resistance, etc. while maintaining transparency and low yellowness.

The present invention was made in consideration of this situation, and the object of the present invention is to obtain a polyimide film with a low coefficient of linear expansion, excellent heat resistance, and a small change in yellowness even when heat treated at 400 ° C. or higher. The object is to provide an imide-amic acid copolymer, which is a precursor of a mead resin, a method for producing the same, a varnish containing the copolymer, and a polyimide film.

The present inventors have discovered that a copolymer containing a combination of specific structural units can solve the above problems, and have completed the invention.

That is, the present invention relates to [1] to [16] below.

[1] It includes a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2), and the molar ratio of the repeating unit represented by the formula (1) and the repeating unit represented by the formula (2) [(1)/(2)] A, 5/95 to 60/40, imide-amic acid copolymer.

[Formula 1]

(In formula (1), A ¹ is a tetravalent aromatic group with 4 to 39 carbon atoms or an aliphatic group with a norbonane skeleton, and -O-, -SO ₂ -, -CO-, -CH ₂ -, - as a linking group. It may have at least one selected from the group consisting of C(CH ₃ ) ₂ -, -C ₂ H ₄ O-, and -S-, and B ¹ is a group represented by the above general formula (3). (2), A ² is a tetravalent aromatic group having 4 to 39 carbon atoms, and -O-, -SO ₂ -, -CO-, -CH ₂ -, -C(CH ₃ ) ₂ -, -C as a bonding group. ₂ H ₄ It may have at least one selected from the group consisting of O-, -OCO-, -COO-, -NHCO-, -CONH-, and -S-, and B ² is represented by the general formula (3) above. It is ^a group represented by, ^and X ^{1 and} , represents a group represented by -COO-, or a group represented by -OCO-. R ¹ , R ² , and R ³ each independently represent an organic group having 1 to 20 carbon atoms. h, i, j, k are It is an integer from 0 to 4.)

[2] The imide-amic acid copolymer according to [1] above, wherein the weight average molecular weight is 10,000 or more and 300,000 or less.

[3] A group in which the above A ¹ is composed of a group represented by the following formula (4), a group represented by the following formula (5), a group represented by the following formula (6), and a group represented by the following formula (7) The imide-amic acid copolymer according to [1] or [2] above, which is at least one selected from the group consisting of:

[Formula 2]

[4] The imide-amic acid copolymer according to any one of [1] to [3] above, wherein A ² is a group represented by the following formula (8).

[Formula 3]

[5] It has an imide repeating structural unit and an amidic acid repeating structural unit,

The imide repeating structural unit has a structural unit A1A derived from tetracarboxylic dianhydride and a structural unit B1B derived from diamine,

The amic acid repeating structural unit has a structural unit A2A derived from tetracarboxylic dianhydride and a structural unit B2B derived from diamine,

The structural unit A1A contains a structural unit derived from an aromatic tetracarboxylic dianhydride or a structural unit derived from an aliphatic tetracarboxylic dianhydride having a norbonane skeleton,

The structural unit A2A contains a structural unit derived from aromatic tetracarboxylic dianhydride,

The imide-amic acid copolymer according to any one of [1] to [4] above, wherein the structural units B1B and B2B include a structural unit (B11) derived from diamine represented by the following general formula (b11).

[Formula 4]

(In formula (b11), Y ¹ and Y ² each independently represent a group represented by -COO- or a group represented by -OCO-. R ¹ , R ² , and R ³ each independently represent a group represented by 1 carbon atom. Represents ~20 organic groups. h, i, j, k are integers from 0 to 4.)

[6] The structural unit A2A includes a structural unit (A21) derived from aromatic tetracarboxylic dianhydride (a21),

The structural unit (A21) is expressed as a structural unit (A211) derived from a compound represented by the following formula (a211), a structural unit (A212) derived from a compound represented by the following formula (a212), and the following formula (a213) From the group consisting of a structural unit (A213) derived from a compound represented by the following formula (a214), a structural unit (A214) derived from a compound represented by the following formula (a215), and a structural unit (A215) derived from a compound represented by the following formula The imide-amic acid copolymer according to [5] above, comprising at least one selected.

[Formula 5]

[7] The structural unit A1A is at least selected from the group consisting of a structural unit (A11) derived from a compound represented by the following formula (a11), and a structural unit (A12) derived from a compound represented by the following formula (a12) The imide-amic acid copolymer according to [5] or [6] above, comprising one.

[Formula 6]

[8] A varnish obtained by dissolving the copolymer according to any one of [1] to [7] above in an organic solvent.

[9] A polyimide film comprising a polyimide resin obtained by imidizing the amidic acid moiety in the copolymer according to any one of [1] to [7] above.

[10] The polyimide film according to [9], wherein the polyimide film has a glass transition temperature of 430°C or higher.

[11] The polyimide film according to [9] or [10] above, wherein the yellowness YI1 after heat treatment at 430°C for 1 hour twice and the yellowness YI0 before heat treatment satisfy the following formula (8).

ΔYI=YI1-YI0≤20 (8)

[12] A laminate comprising the polyimide film according to any one of [9] to [11] above and at least one inorganic layer.

[13] The laminate according to [12], wherein the yellowness YI1 after heat treatment at 430°C for 1 hour twice and the yellowness YI0 before heat treatment satisfy the following equation (8).

ΔYI=YI1-YI0≤20 (8)

[14] A production method for producing the copolymer according to any one of [1] to [7] above, comprising the following steps 1 and 2:

Process 1: Process of obtaining an imide oligomer by reacting the tetracarboxylic acid component constituting the imide portion with the diamine component

Step 2: React the imide oligomer obtained in Step 1 with the tetracarboxylic acid component and diamine component constituting the amic acid moiety to produce an imide-amic acid copolymer containing a repeating unit consisting of an imide moiety and an amic acid moiety. process of obtaining

[15] The method for producing the imide-amic acid copolymer according to [14] above, wherein the imide oligomer obtained in step 1 has amino groups at both ends of the main chain of the molecular chain.

[16] In step 1, the molar ratio of the diamine component to the tetracarboxylic acid component (diamine/tetracarboxylic acid) is 1.01 to 2, the imide-amic acid copolymer according to [14] or [15] above. Manufacturing method.

According to the present invention, an imide-amic acid copolymer, which is a precursor of a polyimide resin, can be obtained to obtain a polyimide film with a low coefficient of linear expansion, excellent heat resistance, and small change in yellowness even when heat treated at 400 ° C. or higher. and a method for producing the same, a varnish containing this copolymer, and a polyimide film.

[Imide-amic acid copolymer]

The imide-amic acid copolymer of the present invention includes a repeating unit represented by the following formula (1), a repeating unit represented by the following formula (2), and a repeating unit represented by the formula (1) and the formula ( It is an imide-amic acid copolymer in which the molar ratio [(1)/(2)] of the repeating unit represented by 2) is 5/95 to 60/40.

[Formula 7]

(In formula (1), A ¹ is a tetravalent aromatic group with 4 to 39 carbon atoms or an aliphatic group with a norbonane skeleton, and -O-, -SO ₂ -, -CO-, -CH ₂ -, - as a linking group. It may have at least one selected from the group consisting of C(CH ₃ ) ₂ -, -C ₂ H ₄ O-, and -S-, and B ¹ is a group represented by the above general formula (3).

In formula (2), A ² is a tetravalent aromatic group having 4 to 39 carbon atoms, and -O-, -SO ₂ -, -CO-, -CH ₂ -, -C(CH ₃ ) ₂ -, - as a linking group. C ₂ H ₄ O-, -OCO-, -COO-, -NHCO-, -CONH-, and -S- may have at least one selected from the group consisting of, and B ² is represented by the general formula (3) ), and X ¹ and X ² are each independently a hydrogen atom, an alkyl group with 1 to 6 carbon atoms, or an alkylsilyl group with 3 to 9 carbon atoms.

In formula (3), Y ¹ and Y ² each independently represent a group represented by -COO- or a group represented by -OCO-. R ¹ , R ² , and R ³ each independently represent an organic group having 1 to 20 carbon atoms. h, i, j, k are integers from 0 to 4.)

The imide-amic acid copolymer of the present invention is excellent as a raw material for polyimide film, and the obtained polyimide film has a low linear expansion coefficient, excellent heat resistance, and shows little change in yellowness even when heat treated at 400°C or higher. The exact reason for its excellent properties is not clear, but it is thought to be as follows.

It is believed that a copolymer composed of a component derived from tetracarboxylic acid containing an aromatic group and the specific diamine component described above is compatible with the low linear expansion coefficient and high heat resistance required for TFT substrates and the like.

On the other hand, among polyamic acids containing a component derived from tetracarboxylic acid consisting of an aromatic group, thermal imidization during film formation is difficult to occur and some do not exhibit good physical properties when film formation. The imide of the present invention- In the amic acid copolymer, it is believed that the physical properties after forming into a film are excellent because some of the components are imidized in advance during polymer polymerization.

Most of the alicyclic tetracarboxylic dianhydrides generally have low reactivity, so it is difficult to obtain polyamic acid with sufficient molecular weight, and it is difficult to develop good physical properties even if it is formed into a film. However, in the imide-amic acid copolymer of the present invention, Since some of the components derived from alicyclic tetracarboxylic acid are imidized in advance during polymer polymerization, an imide-amic acid copolymer with a higher molecular weight than polyamic acid is obtained and is believed to have excellent physical properties after film formation. Furthermore, the imide-amic acid copolymer of the present invention is thought to have excellent physical properties after film formation because the imide moiety and the amic acid moiety have a specific structure.

<Repeating unit (imide portion) expressed in equation (1)>

In the imide-amic acid copolymer of the present invention, the repeating unit represented by formula (1) is an imide moiety.

In the above formula (1), A ¹ is a tetravalent aromatic group having 4 to 39 carbon atoms or an aliphatic group having a norbonane skeleton, and as a linking group, -O-, -SO ₂ -, -CO-, -CH ₂ -, It may have at least one selected from the group consisting of -C(CH ₃ ) ₂ -, -C ₂ H ₄ O-, and -S-.

A ¹ is obtained by excluding two dicarboxylic anhydride moieties (four carboxyl groups) from tetracarboxylic dianhydride, and A ¹ and the four carbonyl groups bonded to it are structural units derived from tetracarboxylic dianhydride.

Here, a tetravalent aromatic group means that all four carbons bonded to the imide group are aromatic carbons. In addition, the above linking group refers to a linking group that bonds each aromatic ring when A ¹ contains two or more aromatic rings. Meanwhile, the coupler is not limited to these.

When A ¹ is an aromatic group, the heat resistance of the polyimide becomes good, so it is preferable.

Additionally, an aliphatic group having a tetravalent norbornane skeleton means that all four carbons bonded to the imide group are aliphatic carbons, and at least one has a norbornane skeleton. In addition, the above linking group refers to a linking group that binds each ring structure when A ¹ contains two or more ring structures. Meanwhile, the coupler is not limited to these.

It is preferable that A ¹ is an aliphatic group having a nobonane skeleton because the heat resistance of the polyimide becomes good.

A ¹ is a tetravalent aromatic group having 4 to 39 carbon atoms or an aliphatic group having a norbonane skeleton, and among them, preferably a group represented by the formula (4) below, a group represented by the formula (5) below, or a group represented by the formula (5) below, It is at least one selected from the group consisting of a group represented by the formula (6) and a group represented by the formula (7) below, more preferably a group represented by the formula (4) below and a group represented by the formula (7) below. It is a group represented, and more preferably, it is a group represented by the following formula (4).

The tetravalent aromatic group having 4 to 39 carbon atoms in A ¹ is preferably a group represented by the following formula (4) and a group represented by the following formula (7), and the novo group having 4 to 39 carbon atoms in A ¹ As an aliphatic group having an egg skeletal structure, a group represented by the following formula (5) and a group represented by the following formula (6) are preferable.

[Formula 8]

In the above formula (1), B ¹ is a group represented by the following general formula (3).

B ¹ is a diamine obtained by excluding two amino groups and is a structural unit derived from diamine. Among these, a group preferably consisting of a group represented by the following formula (3a) and a group represented by the following formula (3b) There is at least one selected from . In addition, it is preferable that B ¹ in the above formula (1) does not include a group represented by the following formula (3c).

[Formula 9]

(In formula (3), Y ¹ and Y ² each independently represent a group represented by -COO- or a group represented by -OCO-. R ¹ , R ² , and R ³ each independently represent a group represented by 1 carbon atom. Represents ~20 organic groups. h, i, j, k are integers from 0 to 4.)

<Repeating unit (amidic acid portion) represented by formula (2)>

In the imide-amic acid copolymer of the present invention, the repeating unit represented by formula (2) is an amic acid moiety.

In the above formula (2), A ² is a tetravalent aromatic group having 4 to 39 carbon atoms, and -O-, -SO ₂ -, -CO-, -CH ₂ -, -C(CH ₃ ) ₂ - as a linking group. , -C ₂ H ₄ O-, -OCO-, -COO-, -NHCO-, -CONH-, and -S-. A ² may be different from or the same as A ¹ , and is preferably a tetravalent aromatic group having 4 to 39 carbon atoms different from A ¹ .

A ² is obtained by excluding two dicarboxylic anhydride moieties (four carboxyl groups) from tetracarboxylic dianhydride, and A ² and the four carbonyl groups bonded to it are structural units derived from tetracarboxylic dianhydride.

Here, a tetravalent aromatic group means that all four carbons bonded to the imide group are aromatic carbons. In addition, the above linking group refers to a linking group that bonds each aromatic ring when A ² contains two or more aromatic rings. Meanwhile, the coupler is not limited to these. When A ² is an aromatic group, it is preferable because the heat resistance of the polyimide becomes good.

A ² is a tetravalent aromatic group having 4 to 39 carbon atoms, and among these, it is preferably a group represented by the following formula (8), and more preferably a group represented by the following formula (8a).

[Formula 10]

In the above formula ( ^{2), X 1 and}

In the above formula (2), B ² is a group represented by the following general formula (3).

B ² is a structural unit obtained by removing two amino groups from diamine and is derived from diamine, and among them, a group preferably consisting of a group represented by the following formula (3a) and a group represented by the following formula (3b) There is at least one selected from . In addition, it is preferable that B ² in the above formula (1) does not include a group represented by the following formula (3c).

[Formula 11]

(In formula (3), Y ¹ and Y ² each independently represent a group represented by -COO- or a group represented by -OCO-. R ¹ , R ² , and R ³ each independently represent a group represented by 1 carbon atom. Represents ~20 organic groups. h, i, j, k are integers from 0 to 4.)

<Composition of imide-amic acid copolymer>

In the imide-amic acid copolymer of the present invention, the molar ratio [(1)/(2)] of the repeating unit represented by formula (1) and the repeating unit represented by formula (2) is 5/95 to 60. It is /40.

The molar ratio [(1)/(2)] of the repeating unit represented by formula (1) and the repeating unit represented by formula (2) is 5/ from the viewpoint of transparency, low yellowness, high heat resistance, and low linear expansion coefficient. It is 95 to 60/40, preferably 10/90 to 60/40, and more preferably 15/85 to 60/40.

The mass ratio of the sum of the repeating units represented by formula (1) and the repeating units represented by formula (2) for the imide-amic acid copolymer of the present invention is preferably 50% by mass or more, and more preferably Preferably it is 70 mass% or more, more preferably 80 mass% or more, even more preferably 82 mass% or more, even more preferably 85 mass% or more, and even more preferably 90 mass% or more. , more preferably 95 mass% or more, and there is no upper limit, and it is 100 mass% or less.

The molar ratio of the total of the repeating unit represented by formula (1) and the repeating unit represented by formula (2) for the imide-amic acid copolymer of the present invention is preferably 50 mol% or more, and more preferably Preferably it is 70 mol% or more, more preferably 80 mol% or more, even more preferably 82 mol% or more, even more preferably 85 mol% or more, and even more preferably 90 mol% or more. , More preferably, it is 95 mol% or more, and the upper limit is not limited and is 100 mol% or less.

In the imide-amic acid copolymer of the present invention, repeating units other than the repeating unit represented by formula (1) and the repeating unit represented by formula (2) are included within a range that does not impair the effect of the present invention. However, repeating units other than the repeating unit represented by formula (1) and the repeating unit represented by formula (2) include those derived from tetracarboxylic dianhydride of the repeating unit represented by formula (1). It is preferable to replace the structural unit with the structural unit derived from tetracarboxylic dianhydride of the repeating unit represented by formula (2). Specifically, a repeating unit represented by the following formula (1a) and a repeating unit represented by the following formula (2a) can be mentioned. The repeating unit represented by formula (1a) and the repeating unit represented by formula (2a) are the repeating unit represented by formula (1) and formula (2) in the imide-amic acid copolymer of the present invention. It may be present in the combined portion of the displayed repeating unit.

[Formula 12]

(In equation (1a), A ² is the same as A ² in equation (2), and B ¹ is the same as B ¹ in equation (1). In equation (2a), A ¹ is the same as A in equation (1) It is the same as ¹ , and B ² , X ¹ , and X ² are the same as B ² , X ¹ , and X ² in equation (2), respectively.)

In the imide-amic acid copolymer of the present invention, a repeating unit represented by formula (1), a repeating unit represented by formula (2), a repeating unit represented by formula (1a), and a repeating unit represented by formula (2a) Repeating units other than the repeating unit include structural units derived from tetracarboxylic dianhydride and structural units derived from diamine as exemplified in the section <Each structural unit of imide-amic acid copolymer> described later. Repeating units can be arbitrarily combined.

Among these repeating units, structural units derived from tetracarboxylic dianhydride include the group represented by the formula (4), the group represented by the formula (5), the group represented by the formula (6), and the formula A structural unit containing the group represented by (7) or the group represented by the above formula (8) as part of the structural unit is preferable, and the imide portion includes the group represented by the above formula (4) and the group represented by (5). A structural unit containing the group represented by the group represented by (6) as a structural unit or a part of the group represented by the above formula (7) is more preferable, and the amic acid moiety contains the group represented by the above formula (8) as a structural unit. A structural unit included as part of is more preferable.

The number average molecular weight of the imide-amic acid copolymer of the present invention is preferably 5,000 to 500,000 from the viewpoint of mechanical strength of the resulting polyimide film. In addition, from the same viewpoint, the weight average molecular weight (Mw) of the imide-amic acid copolymer of the present invention is preferably 10,000 or more and 800,000 or less, more preferably 10,000 or more and 300,000 or less, and even more preferably It is above 100,000 and below 300,000. Meanwhile, the number average molecular weight or weight average molecular weight of the copolymer can be obtained, for example, from the standard polymethyl methacrylate (PMMA) conversion value obtained by gel filtration chromatography measurement.

<Each structural unit of imide-amic acid copolymer>

The imide-amic acid copolymer of the present invention includes a repeating unit represented by the formula (1), a repeating unit represented by the formula (2), and a repeating unit represented by the formula (1) and the formula ( It is a copolymer in which the molar ratio [(1)/(2)] of the repeating unit represented by 2) is 5/95 to 60/40. Preferred structural units constituting this copolymer will be described below.

The imide-amic acid copolymer of the present invention has an imide repeating structural unit and an amic acid repeating structural unit,

The imide repeating structural unit has a structural unit A1A derived from tetracarboxylic dianhydride and a structural unit B1B derived from diamine,

The amic acid repeating structural unit has a structural unit A2A derived from tetracarboxylic dianhydride and a structural unit B2B derived from diamine,

The structural unit A1A contains a structural unit derived from an aromatic tetracarboxylic dianhydride or a structural unit derived from an aliphatic tetracarboxylic dianhydride having a norbonane skeleton,

The structural unit A2A contains a structural unit derived from aromatic tetracarboxylic dianhydride,

It is preferable that the structural units B1B and B2B contain a structural unit (B11) derived from diamine represented by the following general formula (b11).

[Formula 13]

(In formula (b11), Y ¹ and Y ² each independently represent a group represented by -COO- or a group represented by -OCO-. R ¹ , R ² , and R ³ each independently represent a group represented by 1 carbon atom. Represents ~20 organic groups. h, i, j, k are integers from 0 to 4.)

(Constitutive unit A1A)

The structural unit A1A is a structural unit derived from tetracarboxylic dianhydride that occupies the imide portion corresponding to the repeating unit represented by formula (1) of the copolymer of the present invention, and is derived from aromatic tetracarboxylic dianhydride. It contains structural units derived from aliphatic tetracarboxylic dianhydride having a unit or nobonane skeleton.

Structural unit A1A is not limited as long as it includes a structural unit derived from aromatic tetracarboxylic dianhydride or a structural unit derived from aliphatic tetracarboxylic dianhydride having a norbonane skeleton, but structural unit A1A has the following formula ( It is preferable to include at least one selected from the group consisting of a structural unit (A11) derived from a compound represented by a11) and a structural unit (A12) derived from a compound represented by the following formula (a12).

[Formula 14]

The compound represented by formula (a11) is 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF).

It is preferable to include the structural unit (A11) derived from the compound represented by formula (a11) because transparency, low yellowness, and high heat resistance are achieved.

The compound represented by formula (a12) is 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (6FDA).

It is preferable to include the structural unit (A12) derived from the compound represented by formula (a12) because transparency, low yellowness, and high heat resistance are achieved.

When structural unit A1A contains structural unit (A11), the content ratio of structural unit (A11) in structural unit A1A is preferably 50 mol% or more, more preferably 55 mol% or more, and further Preferably it is 60 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, and even more preferably 95 mol% or more. The upper limit of the content ratio of the structural unit (A11) is not particularly limited and is 100 mol% or less. The structural unit A1A may consist of only the structural unit (A11).

When structural unit A1A contains structural unit (A12), the content ratio of structural unit (A12) in structural unit A1A is preferably 50 mol% or more, more preferably 55 mol% or more, and further Preferably it is 60 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, and even more preferably 95 mol% or more. The upper limit of the content ratio of the structural unit (A12) is not particularly limited and is 100 mol% or less. The structural unit A1A may consist of only the structural unit (A12).

When structural unit A1A includes structural unit (A11) and structural unit (A12), the total content ratio of structural unit (A11) and structural unit (A12) in structural unit A1A is preferably 50 mol%. or more, more preferably 55 mol% or more, even more preferably 60 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, and even more preferably It is more than 95 mol%. The upper limit of the total content ratio of the structural unit (A11) and the structural unit (A12) is not particularly limited and is 100 mol% or less. Constituent unit A1A may consist of only the structural unit (A11) and the structural unit (A12).

The structural unit A1A may include structural units other than the structural unit (A11) and the structural unit (A12). The tetracarboxylic dianhydride giving such structural units is not particularly limited as long as it is aromatic tetracarboxylic dianhydride or aliphatic tetracarboxylic dianhydride having a norbonane skeleton.

The number of structural units arbitrarily included in structural unit A1A may be one, or two or more types may be used.

In addition, in the imide portion of the copolymer of the present invention, the tetracarboxylic dianhydride that gives the structural unit derived from tetracarboxylic dianhydride that occupies the imide portion other than structural unit A1A is 1, 2, and 4. ,5-cyclohexanetetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclopentanetetracarboxylic dianhydride, bicyclo[2.2.2] Alicyclic tetracarboxylic dianhydride such as octa-7-en-2,3,5,6-tetracarboxylic dianhydride and dicyclohexyltetracarboxylic dianhydride, and 1,2,3,4-butane tetrahydride. and aliphatic tetracarboxylic dianhydrides such as carboxylic dianhydride.

Meanwhile, in this specification, aromatic tetracarboxylic dianhydride refers to tetracarboxylic dianhydride containing at least one aromatic ring, and alicyclic tetracarboxylic dianhydride refers to tetracarboxylic dianhydride containing at least one alicyclic ring and also containing an aromatic ring. It means tetracarboxylic dianhydride that does not contain, and aliphatic tetracarboxylic dianhydride means tetracarboxylic dianhydride that does not contain either an aromatic ring or an alicyclic ring.

(Constitutive unit B1B)

The structural unit B1B is a structural unit derived from diamine occupied in the imide portion corresponding to the repeating unit represented by formula (1) of the copolymer of the present invention, and is derived from diamine represented by the general formula (b11) below. Includes unit (B11).

[Formula 15]

(In formula (b11), Y ¹ and Y ² each independently represent a group represented by -COO- or a group represented by -OCO-. R ¹ , R ² , and R ³ each independently represent a group represented by 1 carbon atom. Represents ~20 organic groups. h, i, j, k are integers from 0 to 4.)

When structural unit B1B contains structural unit (B11), the content ratio of structural unit (B11) in structural unit B1B is preferably 50 mol% or more, more preferably 55 mol% or more, and further Preferably it is 60 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, and even more preferably 95 mol% or more. The upper limit of the content ratio of the structural unit (B11) is not particularly limited and is 100 mol% or less. The structural unit B1B may consist of only the structural unit (B11).

The structural unit (B11) is derived from a compound represented by the following formula (b111), and the structural unit (B111) is derived from a compound represented by the following formula (b112) from the viewpoint of heat resistance, low residual stress, and low linear expansion coefficient. It is preferable to include at least one selected from the group consisting of the structural unit (B112).

[Formula 16]

The compound represented by formula (b111) is 4-aminophenyl-4-aminobenzoate (4-BAAB).

The compound represented by formula (b112) is 1,4-bis(4-aminobenzoyloxy)benzene (ABHQ).

The content ratio of the structural unit (B111) in the structural unit (B11) in the structural unit B1B is preferably 45 mol% or more, more preferably 70 mol% or more, and even more preferably 90 mol% or more. , especially preferably 99 mol% or more. The upper limit of the content ratio is not particularly limited and is 100 mol% or less.

The content ratio of the structural unit (B112) in the structural unit (B11) in the structural unit B1B is preferably 45 mol% or more, more preferably 70 mol% or more, and even more preferably 90 mol% or more. , especially preferably 99 mol% or more. The upper limit of the content ratio is not particularly limited and is 100 mol% or less.

When the structural unit (B11) in the structural unit B1B includes the structural unit (B111) and the structural unit (B112), the content ratio of the sum of the structural unit (B111) and the structural unit (B112) in the structural unit (B11) Silver is preferably 45 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more, and particularly preferably 99 mol% or more. The upper limit of the ratio is not particularly limited and is 100 mol% or less.

In the imide portion of the copolymer of the present invention, diamines that provide structural units derived from diamines occupying the imide portion other than structural unit B1B include 1,4-phenylenediamine, p-xylylenediamine, and 3. , 5-diaminobenzoic acid, 1,5-diaminonaphthalene, 2,2'-dimethylbiphenyl-4,4'-diamine, 4,4'-diaminodiphenylmethane, 1,4-bis[2- (4-aminophenyl)-2-propyl]benzene, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'-diaminobenzanilide, 1-(4-aminophenyl)-2, 3-dihydro-1,3,3-trimethyl-1H-inden-5-amine, α,α'-bis(4-aminophenyl)-1,4-diisopropylbenzene, N,N'-bis( aromatic diamines such as 4-aminophenyl)terephthalamide, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, and 1,4-bis(4-aminophenoxy)benzene; Alicyclic diamines such as 1,3-bis(aminomethyl)cyclohexane and 1,4-bis(aminomethyl)cyclohexane; and aliphatic diamines such as ethylenediamine and hexamethylenediamine.

(Constitutive unit A2A)

The structural unit A2A is a structural unit derived from tetracarboxylic dianhydride that occupies the amic acid moiety corresponding to the repeating unit represented by formula (2) of the copolymer of the present invention, and is derived from aromatic tetracarboxylic dianhydride. It contains a unit, and preferably contains a structural unit derived from an aromatic tetracarboxylic dianhydride that is different from the structural unit A1A.

Structural unit A2A is not limited as long as it contains a structural unit derived from aromatic tetracarboxylic dianhydride, but structural unit A2A includes a structural unit (A21) derived from aromatic tetracarboxylic dianhydride (a21). It is desirable.

Here, the structural unit (A21) is a structural unit (A211) derived from a compound represented by the following formula (a211), a structural unit (A212) derived from a compound represented by the following formula (a212), and the following formula (a213) A structural unit (A213) derived from a compound represented by a structural unit (A214) derived from a compound represented by the following formula (a214), and a structural unit (A215) derived from a compound represented by the following formula (a215) Contains at least one selected from the group.

[Formula 17]

The compound represented by formula (a211) is biphenyltetracarboxylic dianhydride (BPDA), and a specific example thereof is 3,3',4,4'-biphenyltetracarboxylic acid represented by the following formula (a211s) Base acid dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic acid dianhydride (a-BPDA) represented by the formula (a211a) below, 2 represented by the formula (a211i) below, and 2',3,3'-biphenyltetracarboxylic acid dianhydride (i-BPDA). Among them, 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA) represented by the following formula (a211s) is preferable.

[Formula 18]

The compound represented by formula (a212) is p-phenylenebis(trimellitate) dianhydride (TAHQ).

The compound represented by formula (a213) is pyromellitic anhydride (PMDA).

The compound represented by formula (a214) is p-biphenylenebis(trimellitate) dianhydride (BP-TME).

The compound represented by formula (a215) is bis(benzene-3,4-dicarboxylic anhydride) ester (BBDE).

The structural unit (A21) preferably includes the structural unit (A211) from the viewpoint of high heat resistance and low residual stress.

The structural unit A2A may include structural units other than the structural unit (A21). The tetracarboxylic dianhydride that provides such structural units is not particularly limited as long as it is an aromatic tetracarboxylic dianhydride.

The number of structural units arbitrarily included in structural unit A2A may be one, or two or more types may be used.

In addition, in the imide portion of the copolymer of the present invention, the tetracarboxylic dianhydride that gives a structural unit derived from tetracarboxylic dianhydride that occupies the amic acid portion other than structural unit A2A is 1, 2, and 4. ,5-cyclohexanetetracarboxylic dianhydride, norbonane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbonane-5,5'',6,6''-tetracar Monoic acid dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,4,5-cyclopentanetetracarboxylic dianhydride, bicyclo[2.2.2]octa-7-en-2 , alicyclic tetracarboxylic dianhydride such as 3,5,6-tetracarboxylic dianhydride and dicyclohexyltetracarboxylic dianhydride, and aliphatic such as 1,2,3,4-butanetetracarboxylic dianhydride. and tetracarboxylic dianhydride.

The ratio of the total of structural units (A211) to (A215) in the structural unit (A21) is preferably 45 mol% or more, more preferably 70 mol% or more, even more preferably 90 mol% or more, Particularly preferably, it is 99 mol% or more. The upper limit of the ratio is not particularly limited and is 100 mol% or less. The structural unit (A21) may contain at least one type selected from the structural units (A211) to (A215), and may be composed of only one type selected from the structural units (A211) to (A215).

When the structural unit (A21) contains two or more types of structural units selected from structural units (A211) to (A215), there is no particular limitation on the ratio of each structural unit in the structural unit (A21), and the ratio is arbitrary. You can do this.

The proportion of structural unit (A21) in structural unit A2A is preferably 45 mol% or more, more preferably 60 mol% or more, and even more preferably 85 mol% or more. The upper limit of the content ratio is not particularly limited and is 100 mol% or less.

When structural unit A1A contains structural unit (A11) and structural unit A2A contains structural unit (A21), among the structural units derived from tetracarboxylic dianhydride of imide-amic acid copolymer, structural unit ( The molar ratio [(A11)/(A21)] of A11) and the structural unit (A21) is preferably 5/95 to 60/40 from the viewpoint of transparency, low yellowness, high heat resistance, and low linear expansion coefficient. Preferably it is 10/90 to 60/40, and more preferably 15/85 to 60/40.

When structural unit A1A contains a structural unit (A12) and structural unit A2A contains a structural unit (A21), among the structural units derived from tetracarboxylic dianhydride of the imide-amic acid copolymer, the structural unit ( The molar ratio [(A12)/(A21)] of A12) and the structural unit (A21) is preferably 5/95 to 60/40 from the viewpoint of transparency, low yellowness, high heat resistance, and low linear expansion coefficient. Preferably it is 10/90 to 60/40, and more preferably 15/85 to 60/40.

(Constitutive unit B2B)

The structural unit B2B is a structural unit derived from diamine occupied in the amic acid moiety corresponding to the repeating unit represented by formula (2) of the copolymer of the present invention, and is derived from diamine represented by the general formula (b11) below. Includes unit (B11).

[Formula 19]

(In formula (b11), Y ¹ and Y ² each independently represent a group represented by -COO- or a group represented by -OCO-. R ¹ , R ² , and R ³ each independently represent a group represented by 1 carbon atom. Represents ~20 organic groups. h, i, j, k are integers from 0 to 4.)

When structural unit B2B contains structural unit (B11), the content ratio of structural unit (B11) in structural unit B2B is preferably 50 mol% or more, more preferably 55 mol% or more, and further Preferably it is 60 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, and even more preferably 95 mol% or more. The upper limit of the content ratio of the structural unit (B11) is not particularly limited and is 100 mol% or less. The structural unit B2B may consist of only the structural unit (B11).

The structural unit (B11) is a structural unit (B111) derived from a compound represented by the following formula (b111) and a structural unit (B111) derived from a compound represented by the following formula (b112) from the viewpoint of heat resistance, low residual stress and low linear expansion coefficient. It is preferable to include at least one selected from the group consisting of structural units (B112).

[Formula 20]

The compound represented by formula (b111) is 4-aminophenyl-4-aminobenzoate (4-BAAB).

The compound represented by formula (b112) is 1,4-bis(4-aminobenzoyloxy)benzene (ABHQ).

The content ratio of the structural unit (B111) in the structural unit (B11) in the structural unit B2B is preferably 45 mol% or more, more preferably 70 mol% or more, and even more preferably 90 mol% or more. , especially preferably 99 mol% or more. The upper limit of the ratio is not particularly limited and is 100 mol% or less.

The content ratio of the structural unit (B112) in the structural unit (B11) in the structural unit B2B is preferably 45 mol% or more, more preferably 70 mol% or more, and even more preferably 90 mol% or more. , especially preferably 99 mol% or more. The upper limit of the content ratio is not particularly limited and is 100 mol% or less.

When the structural unit (B11) in the structural unit B2B includes the structural unit (B111) and the structural unit (B112), the content ratio of the sum of the structural unit (B111) and the structural unit (B112) in the structural unit (B11) Silver is preferably 45 mol% or more, more preferably 70 mol% or more, further preferably 90 mol% or more, and particularly preferably 99 mol% or more. The upper limit of the ratio is not particularly limited and is 100 mol% or less.

In the amidic acid portion of the copolymer of the present invention, diamines that provide structural units derived from diamines occupied in the imide portion other than structural unit B2B include 1,4-phenylenediamine, p-xylylenediamine, and 3. ,5-diaminobenzoic acid, 1,5-diaminonaphthalene, 2,2'-dimethylbiphenyl-4,4'-diamine, 2,2'-dimethylbiphenyl-4,4'-diamine, 4,4 '-diaminodiphenylmethane, 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene, 2,2-bis(4-aminophenyl)hexafluoropropane, 4,4'- Diaminobenzanilide, 1-(4-aminophenyl)-2,3-dihydro-1,3,3-trimethyl-1H-inden-5-amine, α,α'-bis(4-aminophenyl)- 1,4-diisopropylbenzene, N,N'-bis(4-aminophenyl)terephthalamide, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, and 1,4- aromatic diamines such as bis(4-aminophenoxy)benzene; Alicyclic diamines such as 1,3-bis(aminomethyl)cyclohexane and 1,4-bis(aminomethyl)cyclohexane; and aliphatic diamines such as ethylenediamine and hexamethylenediamine.

[Method for producing imide-amic acid copolymer]

The imide-amic acid copolymer of the present invention may be produced by any method, but is preferably obtained by the following method.

The method for producing the imide-amic acid copolymer of the present invention has the following steps 1 and 2.

Process 1: Process of obtaining an imide oligomer by reacting the tetracarboxylic acid component constituting the imide portion with the diamine component

Step 2: React the imide oligomer obtained in Step 1 with the tetracarboxylic acid component and diamine component constituting the amic acid moiety to produce an imide-amic acid copolymer containing a repeating unit consisting of an imide moiety and an amic acid moiety. process of obtaining

According to the method for producing the imide-amic acid copolymer of the present invention, it becomes possible to control the imide moiety and the amic acid moiety into a specific structure, so that the conventional imide moiety and the amic acid moiety exist randomly. It is different from the amidic acid copolymer, and depending on the thermal imidization reactivity of each component, it is an imide-amic acid copolymer that can be expected to have improved heat resistance and low linear expansion coefficient because it has a polyimide portion and a polyamic acid portion. It is thought that merging can be achieved.

Among them, a suitable method for producing the copolymer of the present invention has the following steps 1 and 2.

Step 1: A compound imparting structural unit A1A derived from tetracarboxylic dianhydride is reacted with a compound imparting structural unit B1B derived from diamine to produce a compound containing an imide repeating structural unit represented by formula (1). Process for obtaining imide oligomers

Step 2: The imide oligomer obtained in Step 1 is reacted with a compound giving structural unit A2A derived from tetracarboxylic dianhydride and a compound giving structural unit B2B derived from diamine to obtain a compound represented by formula (1). Process for obtaining an imide-amic acid copolymer containing an imide repeating structural unit and an amic acid repeating structural unit represented by formula (2)

However, the compound giving structural unit A1A contains aromatic tetracarboxylic dianhydride or aliphatic tetracarboxylic dianhydride having a norbornane skeleton,

The compound giving structural unit A2A contains aromatic tetracarboxylic dianhydride,

The compound giving structural unit B1B and the compound giving B2B include diamine represented by the following general formula (b11).

[Formula 21]

(In formula (b11), Y ¹ and Y ² each independently represent a group represented by -COO- or a group represented by -OCO-. R ¹ , R ² , and R ³ each independently represent a group represented by 1 carbon atom. Represents ~20 organic groups. h, i, j, k are integers from 0 to 4.)

By the production method having the above steps 1 and 2, a copolymer capable of forming a film with excellent transparency and heat resistance and low yellowness can be produced.

Hereinafter, the method for producing the copolymer of the present invention will be described.

<Process 1>

Step 1 is a step of obtaining an imide oligomer by reacting the tetracarboxylic acid component constituting the imide portion containing the portion corresponding to formula (1) with the diamine component.

The tetracarboxylic acid component constituting the imide portion is preferably aromatic tetracarboxylic dianhydride or aliphatic tetracarboxylic dianhydride having a norbonane skeleton.

Step 1 is more preferably a step of obtaining an imide oligomer by reacting a compound giving structural unit A1A derived from tetracarboxylic dianhydride with a compound giving structural unit B1B derived from diamine.

The compound giving structural unit A1A includes aromatic tetracarboxylic dianhydride or aliphatic tetracarboxylic dianhydride having a norbornane skeleton.

Compounds giving structural unit B1B include compounds giving structural unit (B11), and compounds giving structural unit (B11) include compounds represented by the formula (b111) and formula (b112). It is preferable that it contains at least one selected from the group consisting of the following compounds.

The tetracarboxylic acid component used in step 1 preferably contains at least one selected from the group consisting of a compound giving a structural unit (A11) and a compound giving a structural unit (A12), and the entire It is preferable to use the amount in Step 1, and includes tetracarboxylic acid components other than the compound giving the structural unit (A11) and the compound giving the structural unit (A12), within the range that does not impair the effect of the present invention. You may be doing it.

The diamine component used in step 1 preferably contains a compound that provides the structural unit (B11), and to the extent that the effect of the present invention is not impaired, diamine components other than the compound that provides the structural unit (B11) are included. It may contain .

In step 1, the molar ratio of the diamine component to the tetracarboxylic acid component (diamine/tetracarboxylic acid) is preferably 1.01 to 2 mol, more preferably 1.05 to 1.9 mol, and still more preferably 1.1 to 1.7 mol.

There is no particular limitation on the method of reacting the tetracarboxylic acid component and the diamine component to obtain the imide oligomer in Step 1, and known methods can be used.

As a specific reaction method, (1) adding the tetracarboxylic acid component, diamine component, and reaction solvent to the reactor, stirring at 10 to 110°C for 0.5 to 30 hours, and then raising the temperature to perform an imidization reaction, ( 2) After dissolving the diamine component and reaction solvent in the reactor, adding the tetracarboxylic acid component, stirring at 10 to 110°C for 0.5 to 30 hours as needed, and then raising the temperature to perform an imidization reaction, (3) A method in which the tetracarboxylic acid component, diamine component, and reaction solvent are added to the reactor and the temperature is immediately raised to perform an imidization reaction is included.

In the imidization reaction, it is preferable to perform the reaction while removing water generated during production using a Dean-Stark apparatus or the like. By performing this operation, the degree of polymerization and imidization rate can be further increased.

In the above imidization reaction, a known imidization catalyst can be used. Examples of the imidization catalyst include a base catalyst or an acid catalyst.

Base catalysts include pyridine, quinoline, isoquinoline, α-picoline, β-picoline, 2,4-lutidine, 2,6-lutidine, trimethylamine, triethylamine, tripropylamine, and tributylamine. , organic base catalysts such as triethylenediamine, imidazole, N,N-dimethylaniline, and N,N-diethylaniline, and inorganic bases such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate. A catalyst may be mentioned.

Additionally, acid catalysts include crotonic acid, acrylic acid, trans-3-hexenoic acid, cinnamic acid, benzoic acid, methylbenzoic acid, oxybenzoic acid, terephthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid, etc. The above imidization catalysts may be used individually or in combination of two or more types.

Among the above, from the viewpoint of handling, a base catalyst is preferable, an organic base catalyst is more preferable, at least one type selected from triethylamine and triethylenediamine is more preferable, and triethylamine is still more preferable.

The temperature of the imidization reaction is preferably 120 to 250°C, more preferably 160 to 200°C, from the viewpoint of reaction rate and inhibition of gelation, etc. Additionally, the reaction time is preferably 0.5 to 10 hours after the start of outflow of produced water.

The imide oligomer obtained in step 1 is formed from a compound that provides the structural unit (B11) and at least one selected from the group consisting of a compound that gives the structural unit (A11) and a compound that gives the structural unit (A12). It is preferable to have an imide repeating structural unit.

Additionally, the imide oligomer obtained in Step 1 preferably has amino groups at both ends of the main chain of the molecular chain.

By the above method, a solution containing an imide oligomer dissolved in a solvent is obtained. The solution containing the imide oligomer obtained in Step 1 may contain at least a part of the components used as the tetracarboxylic acid component or diamine component in Step 1 as unreacted monomers, to the extent that the effect of the present invention is not impaired. there is.

The number average molecular weight (Mn) of the imide oligomer obtained in Step 1 is preferably 1,000 to 100,000 from the viewpoint of heat resistance and mechanical strength of the resulting polyimide film. In addition, the weight average molecular weight (Mw) is preferably 1,000 to 100,000 from the same viewpoint. Meanwhile, the number average molecular weight or weight average molecular weight of the copolymer can be obtained, for example, from a standard polymethyl methacrylate (PMMA) conversion value measured by gel filtration chromatography or a light scattering method.

<Process 2>

Step 2 in the production method of the present invention is to react the imide oligomer obtained in Step 1 with the tetracarboxylic acid component and diamine component constituting the amic acid moiety to form a repeating unit consisting of the imide moiety and the amic acid moiety. This is a process for obtaining an imide-amic acid copolymer containing.

The tetracarboxylic acid component constituting the amic acid portion used in step 2 is preferably aromatic tetracarboxylic dianhydride.

Step 2 is more preferably performed by reacting the imide oligomer obtained in Step 1 with a compound giving structural unit A2A derived from tetracarboxylic dianhydride and a compound giving structural unit B2B derived from diamine, This is a process for obtaining de-amic acid copolymer.

The compound giving structural unit A2A includes aromatic tetracarboxylic dianhydride.

The compound giving the structural unit B2B preferably includes a compound giving the structural unit (B11), and the compound giving the structural unit (B11) is a compound represented by the formula (b111) and the formula ( It is preferable to include at least one selected from the group consisting of compounds represented by b112).

The tetracarboxylic acid component used in step 2 preferably contains a compound that gives the structural unit (A21), and to the extent that the effect of the present invention is not impaired, compounds other than the compound that gives the structural unit (A21) are used. It may contain tetracarboxylic acid. Tetracarboxylic acid components other than the compound giving the structural unit (A21) include compounds giving the structural unit (A11). However, it is preferable that the tetracarboxylic acid component used in step 2 does not contain a compound that gives the structural unit (A11). In addition, it is preferable to use the entire amount of the compound giving the structural unit (A21) in step 2.

The diamine component used in step 2 preferably contains a compound that provides the structural unit (B11), and to the extent that the effect of the present invention is not impaired, diamine components other than the compound that provides the structural unit (B11) are included. It may contain .

There is no particular limitation on the method of reacting the imide oligomer obtained in Step 1 with the tetracarboxylic acid component and diamine component to obtain the imide-amic acid copolymer in Step 2, and known methods can be used.

As a specific reaction method, (1) the imide oligomer, tetracarboxylic acid component, diamine component, and solvent obtained in Step 1 are added to the reactor, and the reaction temperature is 1 to 72°C in the range of 0 to 120°C, preferably 5 to 80°C. Method of stirring for a while, (2) the imide oligomer and solvent obtained in step 1 are added to the reactor and dissolved, then the tetracarboxylic acid component and diamine component are added, and the mixture is heated at 0 to 120°C, preferably 5 to 80°C. A method of stirring for 1 to 72 hours in the range, etc.

When the reaction is performed at 80°C or lower, the molecular weight of the copolymer obtained in Step 2 does not fluctuate depending on the temperature history during polymerization, and the progress of thermal imidization can be suppressed, making the copolymer stable. It can be manufactured.

By the above method, a copolymer solution containing the imide-amic acid copolymer dissolved in a solvent is obtained.

The concentration of the copolymer in the obtained copolymer solution is preferably 1 to 50 mass%, more preferably 3 to 35 mass%, and still more preferably 5 to 30 mass%.

From the viewpoint of solution viscosity during polyimide film production, the obtained copolymer solution is preferably stored at 23°C for an additional 3 to 10 days after step 2, and then stored at -20°C.

[0070]

The number average molecular weight of the imide-amic acid copolymer obtained by the production method of the present invention is preferably 5,000 to 500,000 from the viewpoint of the mechanical strength of the resulting polyimide film. In addition, from the same viewpoint, the weight average molecular weight (Mw) of the imide-amic acid copolymer obtained by the production method of the present invention is preferably 10,000 or more and 800,000 or less, and more preferably 10,000 or more and 300,000 or less, More preferably, it is 100,000 or more and 300,000 or less. Meanwhile, the number average molecular weight or weight average of the copolymer can be obtained, for example, from the standard polymethyl methacrylate (PMMA) conversion value obtained by gel filtration chromatography measurement.

Next, the raw materials used in this manufacturing method will be explained.

<Tetracarboxylic acid ingredients>

The tetracarboxylic acid component used as a raw material of the imide-amic acid copolymer in this production method is the (constituent unit A1A) clause and (constituent unit A1A) of <Each structural unit of the imide-amic acid copolymer> above. It is preferable to use compounds giving each structural unit described in section A2A).

When the tetracarboxylic acid component used in step 1 of obtaining an imide oligomer contains a compound that provides a structural unit (A11), the compound that gives the structural unit (A11) in the tetracarboxylic acid component used in step 1 The usage ratio is preferably 50 mol% or more, more preferably 55 mol% or more, even more preferably 60 mol% or more, even more preferably 80 mol% or more, and even more preferably 90 mol% or more. It is mol% or more, and even more preferably it is 95 mol% or more. The upper limit of the usage ratio of the compound giving the structural unit (A11) is not particularly limited and is 100 mol% or less. The tetracarboxylic acid component used in Step 1 may consist only of compounds giving structural units (A11).

When the tetracarboxylic acid component used in step 1 of obtaining an imide oligomer contains a compound that imparts the structural unit (A12), the compound that imparts the structural unit (A12) in the tetracarboxylic acid component used in step 1 The usage ratio is preferably 50 mol% or more, more preferably 55 mol% or more, even more preferably 60 mol% or more, even more preferably 80 mol% or more, and even more preferably 90 mol% or more. It is mol% or more, and even more preferably it is 95 mol% or more. The upper limit of the usage ratio of the compound providing the structural unit (A12) is not particularly limited and is 100 mol% or less. The tetracarboxylic acid component used in Step 1 may consist only of compounds giving structural units (A12).

When the tetracarboxylic acid component used in step 1 of obtaining an imide oligomer includes a compound giving a structural unit (A1) and a compound giving a structural unit (A12), the tetracarboxylic acid component used in step 1 The total usage ratio of the compound giving the structural unit (A11) and the compound giving the structural unit (A12) is preferably 50 mol% or more, more preferably 55 mol% or more, and even more preferably 60 mol%. It is mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and even more preferably 95 mol% or more. The upper limit of the total usage ratio of the compound giving the structural unit (A11) and the compound giving the structural unit (A12) is not particularly limited and is 100 mol% or less. The tetracarboxylic acid component used in step 1 may consist only of a compound giving a structural unit (A11) and a compound giving a structural unit (A12).

In addition, the compound giving the structural unit (A11) and the compound giving the structural unit (A12) include the compound represented by the formula (a11) and the compound represented by the formula (a12), respectively, but are limited to these. and may be a derivative thereof within the scope of giving the same structural unit. Examples of the derivative include tetracarboxylic acid corresponding to the compound represented by formula (a11) and the compound represented by formula (a12), and alkyl esters of the tetracarboxylic acid. As the compound giving the structural unit (A11), a compound represented by the formula (a11) is preferable. As the compound giving the structural unit (A12), a compound represented by the formula (a12) is preferable.

Similarly, when the tetracarboxylic acid component used in step 2 of forming the amic acid moiety contains a compound that provides the structural unit (A21), the ratio of the compound that provides the structural unit (A21) is preferably 45. It is mol% or more, more preferably 60 mol% or more, and even more preferably 85 mol% or more. The upper limit of the usage ratio is not particularly limited and is 100 mol% or less.

In addition, the compound giving the structural unit (A21) includes a compound represented by the formula (a211), a compound represented by the formula (a212), a compound represented by the formula (a213), a compound represented by the formula (a214), and A compound represented by the formula (a215) is included, but it is not limited thereto, and may be a derivative thereof within the scope of giving the same structural unit. Examples of the derivative include tetracarboxylic acid corresponding to a compound represented by any one of formulas (a211) to (a215) and alkyl esters of the tetracarboxylic acid. As the compound giving the structural unit (A2), a compound represented by any one of formulas (a211) to (a215) is preferable.

In the tetracarboxylic acid component used as a raw material for the imide-amic acid copolymer in this production method, the molar ratio of the compound giving structural unit (A11) and the compound giving structural unit (A21) [(A11)/ (A21)] is preferably 5/95 to 60/40, more preferably 10/90 to 60/40, and even more preferably from the viewpoint of transparency, low yellowness, high heat resistance, and low linear expansion coefficient. is 15/85~60/40.

In the tetracarboxylic acid component used as a raw material for the imide-amic acid copolymer in this production method, the molar ratio of the compound giving structural unit (A12) and the compound giving structural unit (A21) [(A12)/ (A21)] is preferably 5/95 to 60/40, more preferably 10/90 to 60/40, and even more preferably from the viewpoint of transparency, low yellowness, high heat resistance, and low linear expansion coefficient. is 15/85~60/40.

The ratio of the total of the compounds giving structural units (A211) to (A215) in the compound giving structural unit (A21) is preferably 45 mol% or more, more preferably 70 mol% or more, even more preferably is 90 mol% or more, particularly preferably 99 mol% or more. The upper limit of the ratio is not particularly limited and is 100 mol% or less.

The tetracarboxylic acid component used as a raw material for the imide-amic acid copolymer includes a compound imparting a structural unit (A11), a compound imparting a structural unit (A12), a compound imparting a structural unit (A211), and a structural unit. Compounds other than those that give (A212), compounds that give structural units (A213), compounds that give structural units (A214), and compounds that give structural units (A215) may be included, and these compounds are: There may be one type, or two or more types may be used.

<Diamine ingredients>

The diamine component used as a raw material for the imide-amic acid copolymer in this production method is the section (structural unit B1B) and (structural unit B2B) of <each structural unit of the imide-amic acid copolymer> above. It is preferable to use compounds that provide each structural unit described in the section.

When the diamine component used in step 1 of obtaining an imide oligomer contains a compound that provides a structural unit (B11), the usage ratio of the compound that provides a structural unit (B11) in the diamine component used in step 1 is: Preferably it is 50 mol% or more, more preferably 55 mol% or more, even more preferably 60 mol% or more, even more preferably 80 mol% or more, and even more preferably 90 mol% or more. , and even more preferably 95 mol% or more. The upper limit of the usage ratio of the compound providing the structural unit (B11) is not particularly limited and is 100 mol% or less. The diamine component used in Step 1 may consist only of compounds giving structural units (B11).

Similarly, when the diamine component used in step 2 of forming the amic acid moiety contains a compound that provides a structural unit (B11), use of a compound that provides a structural unit (B11) in the diamine component used in step 2 The ratio is preferably 50 mol% or more, more preferably 55 mol% or more, even more preferably 60 mol% or more, even more preferably 80 mol% or more, and even more preferably 90 mol%. % or more, and even more preferably 95 mol% or more. The upper limit of the usage ratio of the compound providing the structural unit (B11) is not particularly limited and is 100 mol% or less. The diamine component used in step 2 may consist only of compounds giving structural units (B11).

Additionally, the compound providing the structural unit (B11) is preferably at least one selected from the group consisting of a compound providing the structural unit (B111) and a compound providing the structural unit (B112). The usage ratio of the compound giving the structural unit (B111) in the compound giving the structural unit (B11) is preferably 45 mol% or more, more preferably 70 mol% or more, and even more preferably 90 mol%. % or more, and particularly preferably 99 mol% or more. The upper limit of its usage ratio is not particularly limited and is 100 mol% or less. The usage ratio of the compound giving the structural unit (B112) in the compound giving the structural unit (B11) is preferably 45 mol% or more, more preferably 70 mol% or more, and even more preferably 90 mol%. % or more, and particularly preferably 99 mol% or more. The upper limit of its usage ratio is not particularly limited and is 100 mol% or less. The total usage ratio of the compound giving the structural unit (B11) and the compound giving the structural unit (B112) among the compounds giving the structural unit (B11) is preferably 45 mol% or more, and more preferably It is 70 mol% or more, more preferably 90 mol% or more, and especially preferably 99 mol% or more. The upper limit of the total usage ratio is not particularly limited and is 100 mol% or less.

The diamine component used as a raw material for the imide-amic acid copolymer may contain compounds other than the compound that provides the structural unit (B11), and the number of such compounds may be one or two or more.

Examples of the compound giving the structural unit (B11) include diamine, but it is not limited thereto, and may be a derivative thereof within the scope of giving the same structural unit. Examples of the derivative include diisocyanate corresponding to diamine. As the compound that provides the structural unit (B11), diamine is preferable.

In the present invention, the dosage ratio of the tetracarboxylic acid component and the diamine component used in the entire process of producing the copolymer including Step 1 and Step 2 is preferably 0.9 to 1.1 mole of the diamine component per 1 mole of the tetracarboxylic acid component. do.

<End capping agent>

In addition, in the present invention, in the production of the imide-amic acid copolymer, an end capping agent may be used in addition to the tetracarboxylic acid component and diamine component described above. The end capping agent is preferably used in step 2.

Monoamines or dicarboxylic acids are preferred as the end capping agent. The amount of the terminal capping agent introduced is preferably 0.0001 to 0.1 mol, more preferably 0.001 to 0.06 mol, per 1 mol of tetracarboxylic acid component. Monoamine end capping agents include, for example, methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine, and 3-methylbenzylamine. , 3-ethylbenzylamine, aniline, 3-methylaniline, 4-methylaniline, etc. Among these, benzylamine and aniline are preferred. As dicarboxylic acid end capping agents, dicarboxylic acids are preferable, and part of them may be ring-closed. For example, phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2,3-benzophenonedicarboxylic acid, 3,4-benzophenonedicarboxylic acid, cyclopentane-1,2-dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, etc. are mentioned. Among these, phthalic acid and phthalic anhydride are preferable.

<Solvent>

The solvent used in the method for producing the copolymer of the present invention may be any solvent that can dissolve the resulting imide-amic acid copolymer. For example, aprotic solvents, phenol-based solvents, ether-based solvents, carbonate-based solvents, etc. can be mentioned.

Specific examples of aprotic solvents include N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, and 1,3-dimethylimidazoly. Amide-based solvents such as dinon and tetramethylurea, lactone-based solvents such as γ-butyrolactone and γ-valerolactone, phosphorus-containing amide-based solvents such as hexamethylphosphoricamide and hexamethylphosphinetriamide, and dimethylsulfone. , sulfur-containing solvents such as dimethyl sulfoxide and sulfolane, ketone solvents such as acetone, methyl ethyl ketone, cyclohexanone, and methylcyclohexanone, and ester solvents such as acetic acid (2-methoxy-1-methylethyl). etc. can be mentioned.

Specific examples of phenol-based solvents include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6 -Xylenol, 3,4-xylenol, 3,5-xylenol, etc. are mentioned.

Specific examples of ether-based solvents include 1,2-dimethoxyethane, bis(2-methoxyethyl)ether, 1,2-bis(2-methoxyethoxy)ethane, and bis[2-(2-meth). Toxiethoxy)ethyl] ether, tetrahydrofuran, 1,4-dioxane, etc. are mentioned.

Specific examples of carbonate-based solvents include diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, and propylene carbonate.

Among the reaction solvents, amide-based solvents or lactone-based solvents are preferable, amide-based solvents are more preferable, and N-methyl-2-pyrrolidone is still more preferable. The above reaction solvents may be used individually or in mixture of two or more types.

[Varnish]

The varnish of the present invention is obtained by dissolving the imide-amic acid copolymer of the present invention, which is a precursor of a polyimide resin, in an organic solvent. That is, the varnish of the present invention contains the imide-amic acid copolymer of the present invention and an organic solvent, and the imide-amic acid copolymer is dissolved in the organic solvent.

The organic solvent may be any solvent in which the copolymer of the present invention is dissolved, and is not particularly limited, but it is preferable to use the above-mentioned compounds alone or in a mixture of two or more as a solvent used in the production of the copolymer of the present invention.

The varnish of the present invention may be the above-described copolymer solution itself, or may be obtained by adding a diluting solvent to the copolymer solution.

The varnish of the present invention may further contain an imidization catalyst and a dehydration catalyst from the viewpoint of efficiently advancing imidization of the amic acid moiety in the copolymer of the present invention. The imidization catalyst may be an imidization catalyst with a boiling point of 40°C or higher. If it is an imidization catalyst with a boiling point of 40°C or higher, the possibility of volatilization before imidization sufficiently progresses can be avoided.

Examples of the imidization catalyst include amine compounds such as pyridine or picoline; Imidazole compounds such as imidazole, 1,2-dimethylimidazole, 1-benzylimidazole, 1-benzyl-2-methylimidazole, and benzoimidazole; etc. can be mentioned. The above imidization catalysts may be used individually or in combination of two or more types.

Dehydration catalysts include acid anhydrides such as acetic anhydride, propionic anhydride, n-butyric acid anhydride, benzoic acid anhydride, and trifluoroacetic anhydride; Carbodiimide compounds such as dicyclohexylcarbodiimide can be mentioned. These may be used individually or in combination of two or more types.

Since the copolymer contained in the varnish of the present invention has solvent solubility, it can be used as a high-concentration varnish. The varnish of the present invention preferably contains 3 to 40 mass% of the copolymer of the present invention, more preferably contains 5 to 40 mass%, and further preferably contains 6 to 30 mass%. The viscosity of the varnish is preferably 0.1 to 100 Pa·s, and more preferably 0.1 to 20 Pa·s. The viscosity of the varnish is a value measured at 25°C using an E-type viscometer.

In addition, the varnish of the present invention contains an inorganic filler, an adhesion promoter, a release agent, a flame retardant, an ultraviolet stabilizer, a surfactant, a leveling agent, an antifoaming agent, an optical whitening agent, a crosslinking agent, and a polymerization initiator, within the range that does not impair the required properties of the polyimide film. , photosensitizers, and other additives may be included.

The method for producing the varnish of the present invention is not particularly limited, and known methods can be applied.

[Polyimide film]

The polyimide film of the present invention contains a polyimide resin obtained by imidizing the amidic acid moiety in the imide-amic acid copolymer of the present invention. Therefore, the polyimide film of the present invention is excellent in transparency and heat resistance, and has low yellowness.

The polyimide film of the present invention can be manufactured using a varnish formed by dissolving the above-described copolymer in an organic solvent.

There is no particular limitation on the method for producing a polyimide film using the varnish of the present invention, and known methods can be used. For example, after the varnish of the present invention is applied or molded into a film on a smooth support such as a glass plate, metal plate, or plastic, organic solvents such as reaction solvents or diluting solvents contained in the varnish are removed by heating. A polyimide film can be produced by obtaining a copolymer film, imidizing (dehydrating ring closure) the amidic acid site of the copolymer in the copolymer film by heating, and then peeling it from the support.

From the viewpoint of the mechanical strength of the film, the weight average molecular weight (Mw) of the polyimide resin contained in the polyimide film of the present invention is preferably 10,000 to 800,000, more preferably 10,000 to 300,000, and even more preferably It is 100,000~300,000. Meanwhile, the weight average molecular weight of the polyimide resin can be obtained, for example, from the standard polymethyl methacrylate (PMMA) conversion value determined by gel filtration chromatography.

The heating temperature when drying the varnish of the present invention to obtain a copolymer film is preferably 50 to 150°C. The heating temperature when imidizing the copolymer of the present invention by heating is preferably 200 to 500°C, more preferably 300 to 470°C, and still more preferably 400 to 450°C. Moreover, the heating time is preferably 1 minute to 6 hours, more preferably 5 minutes to 2 hours, and still more preferably 15 minutes to 1 hour.

Heating atmospheres include air gas, nitrogen gas, oxygen gas, hydrogen gas, and nitrogen/hydrogen mixed gas. In order to suppress coloring of the resulting polyimide resin, nitrogen gas with an oxygen concentration of 100 ppm or less and hydrogen at a hydrogen concentration are used. A nitrogen/hydrogen mixed gas containing 0.5% or less is preferable.

Meanwhile, the imidization method is not limited to thermal imidization, and chemical imidization can also be applied.

The thickness of the polyimide film of the present invention can be appropriately selected depending on the application, etc., and is preferably 1 to 250 μm, more preferably 5 to 100 μm, and even more preferably 5 to 50 μm.

The thickness of the polyimide film can be easily controlled by adjusting the solid content concentration or viscosity of the varnish.

<Polyimide film physical properties>

By using the imide-amic acid copolymer of the present invention, it is possible to form a polyimide film that has a low linear expansion coefficient and excellent heat resistance, and has a small change in yellowness even after heat treatment. Suitable physical properties of the polyimide film are as follows.

The linear expansion coefficient (range of 100°C to 400°C) is preferably 25 ppm/°C or less, more preferably 20 ppm/°C or less, and even more preferably 15 ppm/°C or less.

The glass transition temperature (Tg) of the polyimide film of the present invention is preferably 430°C or higher, more preferably 450°C or higher, and even more preferably 480°C or higher.

The 1% weight loss temperature (Td1%) is preferably 500°C or higher, more preferably 510°C or higher, and even more preferably 520°C or higher.

Meanwhile, the above-mentioned physical properties in the present invention can be specifically measured by the method described in the Examples.

The polyimide film of the present invention has excellent heat resistance.

As a heat resistance test, when heat treatment at 430°C for 1 hour is performed twice on a film with a thickness of 10 ± 3 μm, the difference between the yellowness (YI1) and the initial yellowness (YI0) is preferably 20.0 or less, and more preferably is 10.0 or less, more preferably 8.0 or less, even more preferably 6.0 or less, and even more preferably 5.0 or less.

In addition, it is preferable that the yellowness YI1 after heat treatment at 430°C for 1 hour is performed twice and the initial yellowness YI0 satisfy the following equation (8).

ΔYI=YI1-YI0≤20 (8)

The heat resistance test method can be specifically performed by the method described in the Examples.

The polyimide film of the present invention is suitably used as a film for various members such as color filters, flexible displays, semiconductor components, and optical members. The polyimide film of the present invention is particularly suitably used as a substrate for image display devices such as liquid crystal displays and OLED displays.

[Laminate]

The laminate of the present invention consists of the polyimide film and at least one inorganic layer. The inorganic layer is preferably laminated on a polyimide film.

Inorganic layers include metal films, semiconductor films, and insulating films.

The laminate of the present invention preferably has at least one layer selected from the group consisting of a metal film, a semiconductor film, and an insulating film laminated on a polyimide film, and at least one layer selected from the group consisting of a metal film and a semiconductor film on a polyimide film. It is more preferable that at least one selected film is laminated, more preferably, the semiconductor film is laminated on the polyimide film, and even more preferably, the insulating film and the semiconductor film are laminated on the polyimide film, and the semiconductor film is laminated on the polyimide film. It is more preferable that the insulating film and the semiconductor film are stacked in this order. By laminating a metal film or a semiconductor film on a polyimide film, an electronic device (conductive film) for purposes such as a touch sensor or OLED can be created on the polyimide film.

Additionally, the laminate of the present invention may have an insulating film between the polyimide film and the metal film or semiconductor film, and preferably has an insulating film. The insulating film is preferably a SiO ₂ film, and the SiO ₂ film functions as a buffer film when forming a metal film or semiconductor film.

Preferred specific examples of the metal film include copper mesh, silver mesh, and the like.

Preferred specific examples of the semiconductor film include at least one selected from the group consisting of indium tin oxide (ITO), amorphous silicon, indium gallium zinc oxide (IGZO), and low temperature polysilicon (LTPS).

On top of these metal films or semiconductor films, another metal film or semiconductor film may be additionally laminated.

The thickness of the metal film or semiconductor film is not particularly limited, and is preferably 1 to 400 nm, more preferably 10 to 300 nm, and still more preferably 20 to 200 nm.

The laminate of the present invention has excellent heat resistance.

As a heat resistance test, when a laminate with a thickness of 10 ± 3 μm is subjected to heat treatment at 430°C for 1 hour twice, the difference between the yellowness (YI1) and the initial yellowness (YI0) is preferably 20.0 or less, and more preferably Preferably it is 10.0 or less, more preferably 8.0 or less, even more preferably 6.0 or less, and even more preferably 5.0 or less.

In addition, it is preferable that the yellowness YI1 after heat treatment at 430°C for 1 hour is performed twice and the initial yellowness YI0 satisfy the following equation (8).

ΔYI=YI1-YI0≤20 (8)

The heat resistance test method can be specifically performed by the method described in the Examples.

Example

Below, the present invention will be specifically explained by way of examples. However, the present invention is not limited at all by these examples.

The physical properties of the polyimide films obtained in Examples and Comparative Examples were measured and evaluated according to the methods shown below.

(1)Film thickness

The film thickness was measured using a micrometer manufactured by Mitsutoyo Co., Ltd.

(2) Glass transition temperature (Tg) (evaluation of heat resistance)

Using a thermomechanical analysis device "TMA/SS6100" manufactured by Hitachi High-Tech Science Co., Ltd., the temperature was raised from 40°C to 550°C under the conditions of a sample size of 3 mm x 20 mm, a load of 50 mN, and a temperature increase rate of 10°C/min in tensile mode. TMA measurement was performed, and the point where the inflection point of stretching was observed was determined as the glass transition temperature.

(3) Coefficient of linear expansion (CTE) (evaluation of heat resistance)

Using a thermomechanical analysis device "TMA/SS6100" manufactured by Hitachi High-Tech Science Co., Ltd., TMA was measured by increasing the temperature from 40°C to 550°C under the conditions of a sample size of 3 mm x 20 mm, a load of 50 mN, and a temperature increase rate of 10°C/min in tensile mode. Measurements were performed and CTEs of 100 to 400°C and 300 to 400°C were determined.

(4) 1% weight loss temperature (Td1%) (evaluation of heat resistance)

The simultaneous differential thermal thermogravimetric measurement device “NEXTA STA200RV” manufactured by Hitachi High-Tech Science Co., Ltd. was used. The sample was heated from 40°C to 150°C at a temperature increase rate of 10°C/min, maintained at 150°C for 30 minutes, and after removing moisture, the temperature was raised to 550°C. Compared to the weight after being maintained at 150°C for 30 minutes, the temperature at which the weight decreased by 1% was set as the 1% weight loss temperature (Td1%). The larger the weight loss temperature, the better the heat resistance.

(5) Heat resistance of polyimide film

In the polyimide films obtained in Examples and Comparative Examples, heat resistance was evaluated for those having a glass transition temperature (Tg) of 430°C or higher.

Heat treatment (maintained for 1 hour at 430°C) was repeated, and the yellowness (YI) before and after heat treatment was measured in accordance with JIS K7136 using a simultaneous color and turbidity meter “COH7700” manufactured by Nippon Sensei Kogyo Co., Ltd. 」 was used to measure it. The smaller the difference between the yellowness (YI) before heat treatment and the yellowness (YI) after heat treatment, the better the heat resistance.

(6) Heat resistance of the laminate

In the polyimide films obtained in Examples and Comparative Examples, with a glass transition temperature (Tg) of 430°C or higher, a laminate (laminated film) consisting of a polyimide film and an inorganic layer (inorganic film) was manufactured as follows. , heat resistance was evaluated.

By imitating the manufacturing process of a display for an image display device, a laminated film was manufactured, heat treatment was performed, and color change after heat treatment was evaluated.

Without peeling off the polyimide films obtained in Examples and Comparative Examples, a SiO ₂ film with a thickness of 300 nm was formed on the polyimide film by sputtering, and an ITO (indium tin oxide) film with a thickness of 1,230 nm was formed thereon.

The obtained laminated film was repeatedly subjected to heat treatment (maintained at 430°C for 1 hour), and the yellowness (YI) before and after heat treatment was measured in accordance with JIS K7136, and was measured by color and Turbidity was measured using a simultaneous turbidity meter “COH7700”. The smaller the difference between the yellowness (YI) before heat treatment and the yellowness (YI) after heat treatment, the better the heat resistance.

The tetracarboxylic acid component and diamine component used in the examples and comparative examples, and their abbreviations, etc. are as follows.

<Tetracarboxylic acid ingredients>

BPAF: 9,9-bis(3,4-dicarboxyphenyl)fluorene dianhydride (manufactured by JFE Chemical Co., Ltd.; compound represented by formula (a11))

6FDA: 4,4'-(hexafluoroisopropylidene)diphthalic anhydride (manufactured by Daikin Industry Co., Ltd.; compound represented by formula (a12))

s-BPDA: 3,3',4,4'-biphenyltetracarboxylic dianhydride (manufactured by Mitsubishi Chemical Corporation, compound represented by formula (a211s))

<Diamine ingredients>

4-BAAB: 4-aminophenyl-4-aminobenzoate (manufactured by Nippon Shunyang Pharmaceutical Co., Ltd.; compound represented by formula (b111))

ABHQ: 1,4-bis(4-aminobenzoyloxy)benzene (manufactured by Mikuni Pharmaceutical Co., Ltd.; compound represented by formula (b112))

TFMB: 2,2'-bis(trifluoromethyl)benzidine (manufactured by Seika Co., Ltd.)

[0104]

The abbreviations of the solvent and catalyst used in the examples and comparative examples are as follows.

NMP: N-methyl-2-pyrrolidone (manufactured by Tokyo Pure Chemical Industry Co., Ltd.)

TEA: Triethylamine (manufactured by Kandong Chemical Co., Ltd.)

<Example 1>

Add 6.848 g (0.030 mole) of 4-BAAB and 30.064 g of NMP to a 500 mL five-necked round bottom flask equipped with a stainless steel half-moon stirring blade, a nitrogen introduction tube, a Dean-Stark with a cooling tube, a thermometer, and a glass end cap. Then, under a nitrogen atmosphere, the internal temperature of the system was set to 70°C, and the mixture was stirred at a rotation speed of 200 rpm to obtain a solution.

To this solution, 9.169 g (0.020 mol) of BPAF and 10.000 g of NMP were added at once, then 0.101 g of TEA and 5.000 g of NMP were added as an imidization catalyst, heated with a mantle heater, and the reaction system was stirred for about 20 minutes. I raised my temperature to 190℃. While collecting the components that were run off, the temperature inside the reaction system was maintained at 190°C and refluxed for 1 hour. After that, 89.468 g of NMP was added, the temperature inside the reaction system was cooled to 50°C, and a solution containing an oligomer having an imide repeating structural unit was obtained.

To the obtained solution, 23.538 g (0.080 mol) of s-BPDA, 15.978 g (0.070 mol) of 4-BAAB, and 30.000 g of NMP were added at once, and stirred at 50°C for 5 hours. After that, NMP was added and homogenized so that the solid concentration was about 15% by mass, thereby obtaining a varnish containing a copolymer (imide-amic acid copolymer) having an imide repeating structural unit and an amic acid repeating structural unit.

Subsequently, the obtained varnish was applied to the glass plate by spin coating, kept at 80°C for 20 minutes on a hot plate, and then heated at 430°C for 60 minutes in a hot air dryer under a nitrogen atmosphere to evaporate the solvent, and polyE I got a mid-film. The physical properties and evaluation results of the film are shown in Table 1.

<Example 2>

A polyimide varnish with a solid content concentration of about 15% by mass was obtained in the same manner as in Example 1, except that 9.169 g (0.020 mole) of BPAF was changed to 8.885 g (0.020 mole) of 6FDA.

Using the obtained varnish, a polyimide film was obtained in the same manner as in Example 1. The physical properties and evaluation results of the film are shown in Table 1.

<Example 3>

Change 9.169 g (0.020 mol) of BPAF to 13.7529 g (0.030 mol) of BPAF, 6.848 g (0.030 mol) of 4-BAAB to 13.934 g (0.040 mol) of ABHQ, and 23.538 g (0.080 mol) of s-BPDA. By the same method as Example 1, except that s-BPDA was changed to 20.5954 g (0.070 mol) and 4-BAAB 15.978 g (0.070 mol) was changed to ABHQ 20.902 g (0.060 mol), the solid concentration was about 15. A polyimide varnish with % by mass was obtained.

Using the obtained varnish, a polyimide film was obtained in the same manner as in Example 1. The physical properties and evaluation results of the film are shown in Table 1.

<Example 4>

The same as Example 1 except that 4-BAAB 6.848g (0.030 mole) was changed to ABHQ 10.451g (0.030 mole), and 4-BAAB 15.978g (0.070 mole) was changed to ABHQ 24.385g (0.070 mole). Through the method, a polyimide varnish with a solid content concentration of about 15% by mass was obtained.

Using the obtained varnish, a polyimide film was obtained in the same manner as in Example 1. The physical properties and evaluation results of the film are shown in Table 1.

<Comparative Example 1>

A polyimide varnish with a solid content concentration of about 15 mass% was obtained in the same manner as in Example 1, except that 6.848 g (0.030 mol) of 4-BAAB was changed to 9.607 g (0.030 mol) of TFMB.

Using the obtained varnish, a polyimide film was obtained in the same manner as in Example 1. The physical properties and evaluation results of the film are shown in Table 1.

<Comparative Example 2>

22.825 g (0.100 mole) of 4-BAAB and 133.275 g of NMP were added to a 500 mL 5-neck round bottom flask equipped with a stainless steel half-moon stirring blade, a nitrogen introduction tube, a Dean-Stark with a cooling tube, a thermometer, and a glass end cap. Then, under a nitrogen atmosphere, the internal temperature of the system was set to 50°C, and the mixture was stirred at a rotation speed of 200 rpm to obtain a solution.

To this solution, 9.169 g (0.020 mol) of BPAF, 23.538 g (0.080 mol) of s-BPDA, and 33.319 g of NMP were added in batches and stirred at room temperature (25°C) for 5 hours.

After that, 148.083 g of NMP was added so that the solid concentration was about 15% by mass, and the mixture was further stirred for about 1 hour to homogenize, thereby obtaining a polyamic acid (PAA) varnish having only an amic acid repeating structural unit.

Using the obtained varnish, a polyimide film was obtained in the same manner as in Example 1. The physical properties and evaluation results of the film are shown in Table 1.

[Table 1]

As shown in Table 1, it can be seen that the polyimide film obtained from the imide-amic acid copolymer of the example having a specific imide repeating structural unit and an amic acid repeating structural unit has a low linear expansion coefficient and excellent heat resistance.

Furthermore, the polyimide film obtained from the imide-amic acid copolymer of Examples 1 to 4 having a specific imide repeating structural unit and an amic acid repeating structural unit, and the laminate of the film and the inorganic film have It had particularly excellent heat resistance.

On the other hand, when the polyimide film obtained from the imide-amic acid copolymer of Comparative Example 1 was subjected to heat treatment in both the heat resistance evaluation of the polyimide film and the heat resistance evaluation of the laminate, a more significant change in yellowness was observed.

In addition, Example 1 and Comparative Example 2 have the same raw material composition for the polyimide film, but the polyimide film of Comparative Example 2 obtained from polyamic acid has a lower glass transition temperature than the polyimide film of Example 1. , the coefficient of linear expansion was also large, so the heat resistance was inferior.

Claims (16)

It includes a repeating unit represented by the following formula (1) and a repeating unit represented by the following formula (2), and the molar ratio of the repeating unit represented by the formula (1) and the repeating unit represented by the formula (2) [(1) )/(2)] A, 5/95 to 60/40, imide-amic acid copolymer.
[Formula 1]

(In formula (1), A ¹ is a tetravalent aromatic group with 4 to 39 carbon atoms or an aliphatic group with a norbonane skeleton, and -O-, -SO ₂ -, -CO-, -CH ₂ -, - as a linking group. It may have at least one selected from the group consisting of C(CH ₃ ) ₂ -, -C ₂ H ₄ O-, and -S-, and B ¹ is a group represented by the above general formula (3).
In formula (2), A ² is a tetravalent aromatic group having 4 to 39 carbon atoms, and -O-, -SO ₂ -, -CO-, -CH ₂ -, -C(CH ₃ ) ₂ -, - as a linking group. C ₂ H ₄ O-, -OCO-, -COO-, -NHCO-, -CONH-, and -S- may have at least one selected from the group consisting of, and B ² is represented by the general formula (3) ), and X ¹ and X ² are each independently a hydrogen atom, an alkyl group with 1 to 6 carbon atoms, or an alkylsilyl group with 3 to 9 carbon atoms.
In formula (3), Y ¹ and Y ² each independently represent a group represented by -COO- or a group represented by -OCO-. R ¹ , R ² , and R ³ each independently represent an organic group having 1 to 20 carbon atoms. h, i, j, k are integers from 0 to 4.) According to paragraph 1,
An imide-amic acid copolymer having a weight average molecular weight of 10,000 or more and 300,000 or less. According to claim 1 or 2,
Said A ¹ is selected from the group consisting of a group represented by the following formula (4), a group represented by the following formula (5), a group represented by the following formula (6), and a group represented by the following formula (7) At least one, imide-amic acid copolymer.
[Formula 2]
According to any one of claims 1 to 3,
An imide-amic acid copolymer wherein the A ² is a group represented by the following formula (8).
[Formula 3]
According to any one of claims 1 to 4,
It has an imide repeating structural unit and an amidic acid repeating structural unit,
The imide repeating structural unit has a structural unit A1A derived from tetracarboxylic dianhydride and a structural unit B1B derived from diamine,
The amic acid repeating structural unit has a structural unit A2A derived from tetracarboxylic dianhydride and a structural unit B2B derived from diamine,
The structural unit A1A contains a structural unit derived from an aromatic tetracarboxylic dianhydride or a structural unit derived from an aliphatic tetracarboxylic dianhydride having a norbonane skeleton,
The structural unit A2A contains a structural unit derived from aromatic tetracarboxylic dianhydride,
An imide-amic acid copolymer in which the structural units B1B and B2B include a structural unit (B11) derived from diamine represented by the following general formula (b11).
[Formula 4]

(In formula (b11), Y ¹ and Y ² each independently represent a group represented by -COO- or a group represented by -OCO-. R ¹ , R ² , and R ³ each independently represent a group represented by 1 carbon atom. Represents ~20 organic groups. h, i, j, k are integers from 0 to 4.) According to clause 5,
The structural unit A2A includes a structural unit (A21) derived from aromatic tetracarboxylic dianhydride (a21),
The structural unit (A21) is expressed as a structural unit (A211) derived from a compound represented by the following formula (a211), a structural unit (A212) derived from a compound represented by the following formula (a212), and the following formula (a213) From the group consisting of a structural unit (A213) derived from a compound represented by the following formula (a214), a structural unit (A214) derived from a compound represented by the following formula (a215), and a structural unit (A215) derived from a compound represented by the following formula An imide-amic acid copolymer comprising at least one selected.
[Formula 5]
According to claim 5 or 6,
The structural unit A1A is at least one selected from the group consisting of a structural unit (A11) derived from a compound represented by the following formula (a11), and a structural unit (A12) derived from a compound represented by the following formula (a12) Including, imide-amic acid copolymer.
[Formula 6]
A varnish formed by dissolving the copolymer according to any one of claims 1 to 7 in an organic solvent. A polyimide film comprising a polyimide resin obtained by imidizing the amidic acid moiety in the copolymer according to any one of claims 1 to 7. According to clause 9,
A polyimide film having a glass transition temperature of 430°C or higher. According to claim 9 or 10,
A polyimide film whose yellowness YI1 and initial yellowness YI0 after heat treatment at 430°C for 1 hour are performed twice satisfy the following equation (8).
ΔYI=YI1-YI0≤20 (8) A laminate comprising the polyimide film according to any one of claims 9 to 11 and at least one inorganic layer. According to clause 12,
A laminate in which the yellowness YI1 after heat treatment at 430°C for 1 hour twice and the initial yellowness YI0 satisfy the following equation (8).
ΔYI=YI1-YI0≤20 (8) A production method for producing the copolymer according to any one of claims 1 to 7, comprising the following steps 1 and 2:
Process 1: Process of obtaining an imide oligomer by reacting the tetracarboxylic acid component constituting the imide portion with the diamine component
Step 2: React the imide oligomer obtained in Step 1 with the tetracarboxylic acid component and diamine component constituting the amic acid moiety to produce an imide-amic acid copolymer containing a repeating unit consisting of an imide moiety and an amic acid moiety. process of obtaining According to clause 14,
A method for producing an imide-amic acid copolymer in which the imide oligomer obtained in step 1 has amino groups at both ends of the main chain of the molecular chain. According to claim 14 or 15,
In step 1, the molar ratio of the diamine component to the tetracarboxylic acid component (diamine/tetracarboxylic acid) is 1.01 to 2. A method for producing an imide-amic acid copolymer.